The number of cases that occur globally is not known,[1] it is estimated that Legionnaires' disease is the cause of between two and nine percent of pneumonia cases that are acquired outside of hospital.[1] There are an estimated 8,000 to 18,000 cases a year in the United States that require hospitalization.[10]Outbreaks of disease account for a minority of cases.[1][13] While it can occur any time of the year it is more common in the summer and fall,[10] the disease is named after the outbreak where it was first identified - the 1976 American Legion convention in Philadelphia.[14]

Those with Legionnaires' disease usually have fever, chills, and a cough, which may be dry or may produce sputum. Almost all with Legionnaires' experience fever, while approximately half have cough with sputum, and one third cough up blood or bloody sputum. Some also have muscle aches, headache, tiredness, loss of appetite, loss of coordination (ataxia), chest pain, or diarrhea and vomiting.[16] Up to half of those with Legionnaires' have gastrointestinal symptoms, and almost half have neurological symptoms,[15] including confusion and impaired cognition.[17] "Relative bradycardia" may also be present, which is low or low-normal heart rate despite the presence of a fever.[18]

Laboratory tests may show that kidney functions, liver functions and electrolyte levels are abnormal, which may include low sodium in the blood. Chest X-rays often show pneumonia with consolidation in the bottom portion of both lungs, it is difficult to distinguish Legionnaires' disease from other types of pneumonia by symptoms or radiologic findings alone; other tests are required for definitive diagnosis.

Persons with Pontiac fever experience fever and muscle aches without pneumonia, they generally recover in two to five days without treatment. For Pontiac fever the time between exposure and symptoms is generally a few hours to two days.

Legionnaires' disease is usually spread by the breathing in of aerosolized water and/or soil contaminated with the Legionella bacteria.[16] Experts have stated that Legionnaires' disease is not transmitted from person to person;[19] in 2014 there was one case of possible spread from someone sick to the caregiver.[20] Rarely, it has been transmitted by direct contact between contaminated water and surgical wounds,[16] the bacteria grows best at warm temperatures.[5] It thrives at water temperatures between 25 and 45 °C (77 and 113 °F), with an optimum temperature of 35 °C (95 °F).[21] Temperatures above 60 °C (140 °F) kill it.[22] Sources where temperatures allow the bacteria to thrive include hot water tanks, cooling towers, and evaporative condensers of large air conditioning systems, such as those commonly found in hotels and large office buildings.[23] Though the first known outbreak was in Philadelphia, Pennsylvania, cases of legionellosis have occurred throughout the world.[15]

L. pneumophila thrives in aquatic systems where it is established within amoebae in a symbiotic relationship.[24]Legionella bacteria survive in water as intracellular parasites of water-dwelling protozoae, such as amoebae. Amoebae are often part of biofilms, and once Legionella and infected amoebae are protected within a biofilm, they are particularly difficult to destroy.[16]

The disease may also be transmitted from contaminated aerosols generated in hot tubs if the disinfection and maintenance program is not followed rigorously.[26] Freshwater ponds, creeks, and ornamental fountains are potential sources of Legionella,[27] the disease is particularly associated with hotels, fountains, cruise ships, and hospitals with complex potable water systems and cooling systems. Respiratory care devices such as humidifiers and nebulizers used with contaminated tap water may contain Legionella species, so using sterile water is very important.[28]

Legionella enters the lung either by aspiration of contaminated water or inhalation of aerosolized contaminated water or soil. In the lung, the bacteria are consumed by macrophages, a type of white blood cell, inside of which the Legionella bacteria multiply causing the death of the macrophage. Once the macrophage dies, the bacteria are released from the dead cell to infect other macrophages. Virulent strains of Legionella kill macrophages by blocking the fusion of phagosomes with lysosomes inside the host cell; normally the bacteria are contained inside the phagosome, which merges with a lysosome, allowing enzymes and other chemicals to break down the invading bacteria.[15]

People of any age may suffer from Legionnaires' disease, but the illness most often affects middle-aged and older persons, particularly those who smoke cigarettes or have chronic lung disease. Immunocompromised people are also at higher risk. Pontiac fever most commonly occurs in persons who are otherwise healthy.

The most useful diagnostic tests detect the bacteria in coughed up mucus, find Legionella antigens in urine samples, or allow comparison of Legionella antibody levels in two blood samples taken 3 to 6 weeks apart. A urine antigen test is simple, quick, and very reliable, but it will only detect Legionella pneumophila serogroup 1, which accounts for 70 percent of disease caused by L. pneumophila, which means use of the urine antigen test alone may miss as many as 30% of cases.[21] This test was developed by Richard Kohler in 1982.[30] When dealing with Legionella pneumophila serogroup 1, the urine antigen test is useful for early detection of Legionnaire's disease and initiation of treatment, and has been helpful in early detection of outbreaks. However, it will not identify the specific subtypes, so it cannot be used to match the person with the environmental source of infection, the Legionella bacteria can be cultured from sputum or other respiratory samples. Legionella stains poorly with Gram stain, stains positive with silver, and is cultured on charcoal yeast extract with iron and cysteine (CYE agar).

A significant under-reporting problem occurs with legionellosis. Even in countries with effective health services and readily available diagnostic testing, about 90 percent of cases of Legionnaires' disease are missed, this is partly due to Legionnaires' disease being a relatively rare form of pneumonia, which many clinicians may not have encountered before and thus may misdiagnose. A further issue is that people with legionellosis can present with a wide range of symptoms, some of which (such as diarrhea) may distract clinicians from making a correct diagnosis.[31]

Although the risk of Legionnaires' disease being spread by large-scale water systems cannot be eliminated, it can be greatly reduced by writing and enforcing a highly detailed, systematic water safety plan appropriate for the specific type of facility involved (office building, hospital, hotel, spa, cruise ship, etc.)[15] Some of the elements that such a plan may include are the following:

Keeping water temperature either above or below the 20–50 °C (68–122 °F) range in which the Legionella bacterium thrives.

Preventing stagnation, for example by removing from a network of pipes any sections that have no outlet (dead ends). Where stagnation is unavoidable, for example when a wing of a hotel is closed for the off-season, systems must be thoroughly disinfected just prior to resuming normal operation.

Preventing the buildup of biofilm, for example by not using (or by replacing) construction materials that encourage its development, and by reducing the quantity of nutrients for bacterial growth that enter the system.

System design (or renovation) that reduces the production of aerosols and reduces human exposure to them, for example by directing them well away from building air intakes.

An effective water safety plan will also cover such matters as training, record-keeping, communication among staff, contingency plans and management responsibilities, the format and content of the plan may be prescribed by public health laws or regulations.[15]

Macrolides (azithromycin) are used in all age groups, while tetracyclines (doxycycline) are prescribed for children above the age of 12 and quinolones (levofloxacin) above the age of 18. Rifampicin can be used in combination with a quinolone or macrolide. It is uncertain whether rifampicin is an effective antibiotic to take for treatment, the Infectious Diseases Society of America does not recommend the use of rifampicin with added regimens. Tetracyclines and erythromycin led to improved outcomes compared to other antibiotics in the original American Legion outbreak, these antibiotics are effective because they have excellent intracellular penetration in Legionella-infected cells. The recommended treatment is 5–10 days of levofloxacin or 3–5 days of azithromycin, but in people who are immunocompromised, have severe disease, or other pre-existing health conditions, longer antibiotic use may be necessary,[16] during outbreaks, prophylactic antibiotics have been successfully used to prevent Legionnaires' disease in high-risk individuals who have possibly been exposed.[16]

The mortality at the original American Legion convention in 1976 was high (29 deaths in 182 infected individuals[33]) because the antibiotics used (including penicillins, cephalosporins, and aminoglycosides) had poor intracellular penetration. Mortality has plunged to less than 5% if therapy is started quickly. Delay in giving the appropriate antibiotic leads to higher mortality.

The fatality rate of Legionnaires' disease has ranged from 5% to 30% during various outbreaks and approaches 50% for nosocomial infections, especially when treatment with antibiotics is delayed.[34] Hospital-acquired Legionella pneumonia has a fatality rate of 28%, and the principal source of infection in such cases is the drinking-water distribution system.[35]

Outbreaks of Legionnaires' disease receive significant media attention. However, this disease usually occurs in single, isolated cases not associated with any recognized outbreak. When outbreaks do occur, they are usually in the summer and early autumn, though cases may occur at any time of year. Most infections occur in those who are middle-aged or older.[34] National surveillance systems and research studies were established early, and in recent years[when?] improved ascertainment and changes in clinical methods of diagnosis have contributed to an upsurge in reported cases in many countries. Environmental studies continue to identify novel sources of infection, leading to regular revisions of guidelines and regulations. About 8,000 to 18,000 cases of Legionnaires' disease occur each year in the United States, according to the Bureau of Communicable Disease Control.[39]

Between 1995 and 2005, over 32,000 cases of Legionnaires' disease and more than 600 outbreaks were reported to the European Working Group for Legionella Infections The data on Legionella are limited in developing countries and Legionella-related illnesses likely are underdiagnosed worldwide.[15] Improvements in diagnosis and surveillance in developing countries would be expected to reveal far higher levels of morbidity and mortality than are currently recognised. Similarly, improved diagnosis of human illness related to Legionella species and serogroups other than Legionella pneumophila would improve knowledge about their incidence and spread.

A 2011 study successfully used modeling to predict the likely number of cases during Legionnaires’ outbreaks based on symptom onset dates from past outbreaks; in this way, the eventual likely size of an outbreak can be predicted, enabling efficient and effective use of public health resources in managing an outbreak.[40]

The first recognized cases of Legionnaires' disease occurred in 1976 in Philadelphia, Pennsylvania, among more than 2000 attendees of an American Legion convention held at the Bellevue-Stratford Hotel, 182 attendees contracted the disease and 29 of them died.[1]

In April 1985, 175 people in Stafford, England, were admitted to the District or Kingsmead Stafford Hospitals with chest infection or pneumonia. A total of 28 people died. Medical diagnosis showed that Legionnaires' disease was responsible and the immediate epidemiological investigation traced the source of the infection to the air-conditioning cooling tower on the roof of Stafford District Hospital.

In March 1999, a large outbreak in the Netherlands occurred during the Westfriese Flora flower exhibition in Bovenkarspel; 318 people became ill and at least 32 people died. This was the second-deadliest outbreak since the 1976 outbreak and possibly the deadliest as several people were buried before Legionnaires' disease had been diagnosed.

The world's largest outbreak of Legionnaires' disease happened in July 2001 with people appearing at the hospital on July 7, in Murcia, Spain. More than 800 suspected cases were recorded by the time the last case was treated on July 22; 636–696 of these cases were estimated and 449 confirmed (so, at least 16,000 people were exposed to the bacterium) and six died, a case-fatality rate around 1%.

In late September 2005, 127 residents of a nursing home in Canada became ill with L. pneumophila. Within a week, 21 of the residents had died. Culture results at first were negative, which is not unusual, as L. pneumophila is a fastidious bacterium, meaning it requires specific nutrients and/or living conditions in order to grow. The source of the outbreak was traced to the air-conditioning cooling towers on the nursing home's roof.

Twelve people were diagnosed with the disease in the Bronx, New York, in December 2014; the source was traced to contaminated cooling towers at a housing development.[42] In July and August 2015, another, unrelated outbreak in the Bronx killed 12 people and made about 120 people sick; the cases arose from a cooling tower on top of a hotel. At the end of September another person died of the disease and 13 were sickened in yet another unrelated outbreak in the Bronx,[43] the cooling towers from which the people were infected in the latter outbreak had been cleaned during the summer outbreak, raising concerns about how well the bacteria could be controlled.[44]

On August 28, 2015, an outbreak of Legionnaire's disease was detected at San Quentin State Prison in Northern California. 81 people were sickened and the cause was sludge that had built up in cooling towers.[45]

Between June 2015 and January 2016, 87 cases of Legionnaires' disease were reported by the Michigan Department of Health and Human Services for the city of Flint, Michigan and surrounding areas. 10 of those cases were fatal.[46]

In November 2017, an outbreak was detected at Hospital de São Francisco Xavier, Lisbon, Portugal, with up to 53 people being diagnosed with the disease and five of them dying from it.[47]

In Quincy, Illinois at the Illinois Veterans home a 2015 outbreak of the disease killed 12 people and sickened more than 50 others, it was believed to be caused by infected water supply. Three more cases have been identified as of November 2017.[48]

1.
Transmission electron microscopy
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Transmission electron microscopy is a microscopy technique in which a beam of electrons is transmitted through an ultra-thin specimen, interacting with the specimen as it passes through it. TEMs are capable of imaging at a higher resolution than light microscopes. This enables the user to examine fine detail—even as small as a single column of atoms. TEM forms a major analysis method in a range of scientific fields, TEMs find application in cancer research, virology, materials science as well as pollution, nanotechnology and semiconductor research. At smaller magnifications TEM image contrast is due to absorption of electrons in the material, due to the thickness, at higher magnifications complex wave interactions modulate the intensity of the image, requiring expert analysis of observed images. The first TEM was built by Max Knoll and Ernst Ruska in 1931, with this group developing the first TEM with resolution greater than that of light in 1933, in 1986, Ruska was awarded the Nobel Prize in physics for the development of transmission electron microscopy. Developments into ultraviolet microscopes, led by Köhler and Rohr, allowed for an increase in resolving power of about a factor of two, however this required more expensive quartz optical components, due to the absorption of UV by glass. At this point it was believed that obtaining an image with sub-micrometer information was simply due to this wavelength constraint. It had earlier recognized by Plücker in 1858 that the deflection of cathode rays was possible by the use of magnetic fields. This effect had been utilized to build primitive cathode ray oscilloscopes as early as 1897 by Ferdinand Braun, indeed, in 1891 it was recognized by Riecke that the cathode rays could be focused by these magnetic fields, allowing for simple lens designs. Later this theory was extended by Hans Busch in his published in 1926. The team consisted of several PhD students including Ernst Ruska and Bodo von Borries, in 1931 the group successfully generated magnified images of mesh grids placed over the anode aperture. The device used two lenses to achieve higher magnifications, arguably the first electron microscope. In that same year, Reinhold Rudenberg, the director of the Siemens company, had patented an electrostatic lens electron microscope. At this time the nature of electrons, which were considered charged matter particles, had not been fully realized until the publication of the De Broglie hypothesis in 1927. In April 1932, Ruska suggested the construction of a new microscope for direct imaging of specimens inserted into the microscope. This goal was achieved in September 1933, using images of cotton fibers, research continued on the electron microscope at Siemens in 1936, the aim of the research was the development improvement of TEM imaging properties, particularly with regard to biological specimens. At this time electron microscopes were being fabricated for specific groups, in 1939 the first commercial electron microscope, pictured, was installed in the Physics department of IG Farben-Werke

2.
Pulmonology
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Pulmonology is a medical speciality that deals with diseases involving the respiratory tract. The term is derived from the Latin word pulmō, pulmōnis, pulmonology is synonymous with pneumology, respirology and respiratory medicine. Pulmonology is known as chest medicine and respiratory medicine in some countries, pulmonology is considered a branch of internal medicine, and is related to intensive care medicine. Pulmonology often involves managing patients who need support and mechanical ventilation. Pulmonologists are specially trained in diseases and conditions of the chest, particularly pneumonia, asthma, tuberculosis, emphysema, in the United Kingdom, Ireland, South Africa, and Australia the term respiratory physician is used to distinguish a physician that practices pulmonology. In Canada, respirology and respirologist are used, surgery of the respiratory tract is generally performed by specialists in cardiothoracic surgery, though minor procedures may be performed by pulmonologists. As mentioned above, pulmonology is closely related to critical care medicine when dealing with patients who require mechanical ventilation, as a result, many pulmonologists are certified to practice critical care medicine in addition to pulmonary medicine. There are fellowship programs that allow physicians to become certified in pulmonary. Interventional pulmonology is a new field within pulmonary medicine that deals with the use of procedures such as bronchoscopy to treat several pulmonary diseases. Interventional pulmonology is yet recognized as a specific medical specialty. Inspection of the hands for signs of cyanosis or clubbing, chest wall, palpation of the cervical lymph nodes, trachea and chest wall movement. Percussion of the fields for dullness or hyper-resonance. Auscultation of the fields for diminished or unusual breath sounds. Rales or rhonchi heard over lung fields with a stethoscope, as many heart diseases can give pulmonary signs, a thorough cardiac investigation is usually included. Sometimes arterial blood gas measurements are also required, spirometry the determination of maximum airflow at a given lung volume as measured by breathing into a dedicated machine, this is the key test to diagnose airflow obstruction. Pulmonologists often perform specialized procedures to get samples from the inside of the chest or inside of the lung and they use radiographic techniques to view vasculature of the lungs and heart to assist with diagnosis. Medication is the most important treatment of most diseases of pulmonology, a common example being the usage of inhalers in the treatment of inflammatory lung conditions such as asthma or chronic obstructive pulmonary disease. Oxygen therapy is necessary in severe respiratory disease

3.
Bacteria
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Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods, Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology, There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are approximately 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants, Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of bodies and bacteria are responsible for the putrefaction stage in this process. In March 2013, data reported by researchers in October 2012, was published and it was suggested that bacteria thrive in the Mariana Trench, which with a depth of up to 11 kilometres is the deepest known part of the oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, You can find microbes everywhere—theyre extremely adaptable to conditions, the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial particularly in the gut flora. However several species of bacteria are pathogenic and cause diseases, including cholera, syphilis, anthrax, leprosy. The most common fatal diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year. In developed countries, antibiotics are used to treat infections and are also used in farming, making antibiotic resistance a growing problem. Once regarded as constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and these evolutionary domains are called Bacteria and Archaea. The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, for about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota, however, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea, here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea

4.
Legionella
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Legionella may be readily visualized with a silver stain or cultured in cysteine-containing media such as BCYE. It is common in environments, including soil and aquatic systems. The bacterium, however, is not transmissible from person to person, furthermore, the side chains of the cell wall carry the bases responsible for the somatic antigen specificity of these organisms. Legionella acquired its name after an outbreak of a mystery disease sickened 221 persons. The outbreak was first noticed among people attending a convention of the American Legion—an association of U. S. military veterans, the convention occurred in Philadelphia during the U. S. Bicentennial year in July 21–24,1976, on January 18,1977, the causative agent was identified as a previously unknown bacterium subsequently named Legionella. See Legionnaires disease for full details, Legionella is traditionally detected by culture on buffered charcoal yeast extract agar. Legionella requires the presence of cysteine and iron to grow, so does not grow on blood agar media used for laboratory-based total viable counts or on-site dipslides. Heat or acid treatment are used to reduce interference from other microbes in the sample. After incubation for up to 10 days, suspect colonies are confirmed as Legionella if they grow on BCYE containing cysteine, immunological techniques are then commonly used to establish the species and/or serogroups of bacteria present in the sample. Consequently, the clinical and environmental prevalence of the bacteria is likely to be underestimated due to false negatives inherent in the current lab methodology. Many hospitals use the Legionella urinary antigen test for detection when Legionella pneumonia is suspected. New techniques for the detection of Legionella in water samples are emerging, including the use of polymerase chain reaction. These technologies can provide much faster results. Government public health surveillance has demonstrated increasing proportions of drinking water–associated outbreaks specifically in healthcare settings, in the natural environment, Legionella lives within amoebae such as Acanthamoeba spp. Upon inhalation, the bacteria can infect alveolar macrophages, subverting the normal host cell machinery to create a niche where the bacteria can replicate and this results in Legionnaires disease and the lesser form, Pontiac fever. Legionella transmission is via inhalation of water droplets from a source that has allowed the organism to grow. Less commonly, transmission can occur via aspiration of drinking water from an infected source, person-to-person transmission has not been demonstrated, though, it could be possible in rare cases

5.
Mist
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Mist is a phenomenon caused by small droplets of water suspended in air. Physically, it is an example of a dispersion and it is most commonly seen where warm, moist air meets sudden cooling, such as in exhaled air in the winter, or when throwing water onto the hot stove of a sauna. It can be created artificially with aerosol canisters if the humidity and it can also occur as part of natural weather, when humid air cools rapidly, for example when the air comes into contact with surfaces that are much cooler than the air. The formation of mist, as of other suspensions, is aided by the presence of nucleation sites on which the suspended water phase can congeal. The only difference between mist and fog is visibility, the phenomenon is called fog if the visibility is one kilometre or less. In the UK the definition of fog is visibility less than 100 metres, otherwise it is known as mist. Mist makes a beam of light visible from the side via refraction and reflection on the water droplets. Scotch mist is a steady drizzle. Mist usually occurs near the shores, and is associated with fog. Mist can be as high as mountain tops when extreme temperatures are low, freezing mist is similar to freezing fog, only the density is less and the visibility greater. Aerosol Aeroponics Brocken spectre Drizzle Haze Spray

6.
Medical diagnosis
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Medical diagnosis is the process of determining which disease or condition explains a persons symptoms and signs. It is most often referred to as diagnosis with the context being implicit. The information required for diagnosis is typically collected from a history, often, one or more diagnostic procedures, such as diagnostic tests, are also done during the process. Sometimes Posthumous diagnosis is considered a kind of medical diagnosis, Diagnosis is often challenging, because many signs and symptoms are nonspecific. For example, redness of the skin, by itself, is a sign of many disorders, thus differential diagnosis, in which several possible explanations are compared and contrasted, must be performed. This involves the correlation of various pieces of information followed by the recognition and differentiation of patterns, occasionally the process is made easy by a sign or symptom that is pathognomonic. Diagnosis is a component of the procedure of a doctors visit. From the point of view of statistics, the procedure involves classification tests. The first recorded examples of medical diagnosis are found in the writings of Imhotep in ancient Egypt, a Babylonian medical textbook, the Diagnostic Handbook written by Esagil-kin-apli, introduced the use of empiricism, logic and rationality in the diagnosis of an illness or disease. Traditional Chinese Medicine, as described in the Yellow Emperors Inner Canon or Huangdi Neijing, specified four diagnostic methods, inspection, auscultation-olfaction, interrogation, hippocrates was known to make diagnoses by tasting his patients urine and smelling their sweat. This article uses diagnostician as any of these person categories, a diagnostic procedure does not necessarily involve elucidation of the etiology of the diseases or conditions of interest, that is, what caused the disease or condition. Such elucidation can be useful to optimize treatment, further specify the prognosis or prevent recurrence of the disease or condition in the future, the initial task is to detect a medical indication to perform a diagnostic procedure. Indications include, Detection of any deviation from what is known to be normal, such as can be described in terms of, for example, anatomy, physiology, pathology, psychology, a complaint expressed by a patient. The fact that a patient has sought a diagnostician can itself be an indication to perform a diagnostic procedure, even during an already ongoing diagnostic procedure, there can be an indication to perform another, separate, diagnostic procedure for another, potentially concomitant, disease or condition. A diagnostic test is any kind of medical test performed to aid in the diagnosis or detection of disease, Diagnostic tests can also be used to provide prognostic information on people with established disease. Processing of the answers, findings or other results, consultations with other providers and specialists in the field may be sought. There are a number of methods or techniques that can be used in a diagnostic procedure, in reality, a diagnostic procedure may involve components of multiple methods. The final result may also remain a list of possible conditions, the resultant diagnostic opinion by this method can be regarded more or less as a diagnosis of exclusion

7.
Water systems
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A water supply system or water supply network is a system of engineered hydrologic and hydraulic components which provide water supply. A water supply system includes, A drainage basin. A raw water collection point where the water accumulates, such as a lake, raw water may be transferred using uncovered ground-level aqueducts, covered tunnels or underground water pipes to water purification facilities. Treated water is transferred using water pipes, Water storage facilities such as reservoirs, water tanks, or water towers. Smaller water systems may store the water in cisterns or pressure vessels, tall buildings may also need to store water locally in pressure vessels in order for the water to reach the upper floors. Additional water pressurizing components such as pumping stations may need to be situated at the outlet of underground or above ground reservoirs or cisterns, a pipe network for distribution of water to the consumers and other usage points. Connections to the sewers are found downstream of the water consumers. Raw water is collected from a water source or from a groundwater source within the watershed that provides the water resource. The raw water is transferred to the water purification facilities using uncovered aqueducts, Water treatment must occur before the product reaches the consumer and afterwards. Water purification usually occurs close to the delivery points to reduce pumping costs. Traditional surface water treatment plants generally consists of three steps, clarification, filtration and disinfection, clarification refers to the separation of particles from the water stream. Chemical addition destabilizes the particle charges and prepares them for either by settling or floating out of the water stream. Sand, anthracite or activated carbon filters refine the water stream, while other methods of disinfection exist, the preferred method is via chlorine addition. Chlorine effectively kills bacteria and most viruses and maintains a residual to protect the supply through the supply network. The product, delivered to the point of consumption, is called potable water if it meets the quality standards required for human consumption. The water is typically pressurised by pumps that pump water into storage tanks constructed at the highest local point in the network, one network may have several such service reservoirs. In small domestic systems, the water may be pressurised by a vessel or even by an underground cistern. This eliminates the need of a water-tower or any other heightened water reserve to supply the water pressure and these systems are usually owned and maintained by local governments, such as cities, or other public entities, but are occasionally operated by a commercial enterprise

8.
Antibiotic
–
Antibiotics, also called antibacterials, are a type of antimicrobial drug used in the treatment and prevention of bacterial infections. They may either kill or inhibit the growth of bacteria, a limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the cold or influenza. Drugs which inhibit viruses are termed antiviral drugs or antivirals rather than antibiotics, sometimes the term antibiotic is used to refer to any substance used against microbes, synonymous with antimicrobial. Some sources distinguish between antibacterial and antibiotic, antibacterials are used in soaps and disinfectants, while antibiotics are used as medicine, Antibiotics revolutionized medicine in the 20th century, and have together with vaccination led to the near eradication of diseases such as tuberculosis in the developed world. However, their effectiveness and easy access led to overuse, especially in raising, prompting bacteria to develop resistance. All classes of antibiotics in use today were first discovered prior to the mid 1980s, substances with antibiotic properties had been used for various purposes since ancient times. Before the early 20th century, treatments for infections were based primarily on medicinal folklore, mixtures with antimicrobial properties that were used in treatments of infections were described over 2000 years ago. Many ancient cultures, including the ancient Egyptians and ancient Greeks, used specially selected mold and plant materials, more recent observations made in the laboratory of antibiosis between microorganisms led to the discovery of natural antibacterials produced by microorganisms. Louis Pasteur observed, if we could intervene in the antagonism observed between some bacteria, it would offer perhaps the greatest hopes for therapeutics. In 1874, physician Sir William Roberts noted that cultures of the mold Penicillium glaucum that is used in the making of types of blue cheese did not display bacterial contamination. In 1876, physicist John Tyndall also contributed to this field, Louis Pasteur conducted research showing that Bacillus anthracis would not grow in the presence of the related mold Penicillium notatum. In his thesis, Duchesne proposed that bacteria and molds engage in a battle for survival. Duchesne observed that E. coli was eliminated by the fungus Penicillium glaucum when they were grown in the same culture. He also observed that when he inoculated animals with lethal doses of typhoid bacilli together with Penicillium glaucum. Unfortunately Duchesnes army service after getting his degree prevented him from doing any further research, Duchesne died of tuberculosis, a disease now treated by antibiotics. In 1928, Sir Alexander Fleming identified penicillin, a molecule produced by molds that kills or stops the growth of certain kinds of bacteria. Fleming was working on a culture of disease-causing bacteria when he noticed the spores of a mold, Penicillium chrysogenum

9.
Fresh water
–
Fresh water is generally characterized by having low concentrations of dissolved salts and other total dissolved solids. The term specifically excludes seawater and brackish water although it does include mineral-rich waters such as chalybeate springs, the term sweet water has been used to describe fresh water in contrast to salt water. The term fresh water does not have the meaning as potable water. Much of the fresh water and ground water is unsuitable for drinking without some form of purification because of the presence of chemical or biological contaminants. It may also be in contact with the underlying underground water. The majority of water on Earth is in ice caps. The source of almost all water is precipitation from the atmosphere, in the form of mist, rain. Fresh water falling as mist, rain or snow contains materials dissolved from the atmosphere and material from the sea, in some cases this acid rain results in pollution of lakes and rivers. In coastal areas fresh water may contain significant concentrations of salts derived from the sea if windy conditions have lifted drops of seawater into the rain-bearing clouds. This can give rise to elevated concentrations of sodium, chloride, magnesium, significant quantities of iron may be transported in this way including the well-documented transfer of iron-rich rainfall falling in Brazil derived from sand-storms in the Sahara in north Africa. Water is an issue for the survival of all living organisms. Some can use water but many organisms including the great majority of higher plants. Out of all the water on Earth, saline water in oceans, seas and saline groundwater make up about 97% of it. Freshwater lakes contain about 87% of this surface water, including 29% in the African Great Lakes, 20% in Lake Baikal in Russia, 21% in the North American Great Lakes. Swamps have most of the balance only a small amount in rivers. In areas with no water on the ground surface, fresh water derived from precipitation may, because of its lower density. Most of the fresh water is frozen in ice sheets. Many areas suffer from lack of distribution of water, such as deserts

10.
Cooling tower
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A cooling tower is a heat rejection device that rejects waste heat to the atmosphere through the cooling of a water stream to a lower temperature. Common applications include cooling the water used in oil refineries, petrochemical and other chemical plants, thermal power stations. The classification is based on the type of air induction into the tower, although these large towers are very prominent, the vast majority of cooling towers are much smaller, including many units installed on or near buildings to discharge heat from air conditioning. Cooling towers originated in the 19th century through the development of condensers for use with the steam engine, condensers use relatively cool water, via various means, to condense the steam coming out of the cylinders or turbines. This reduces the pressure, which in turn reduces the steam consumption. However the condensers require a supply of cooling water, without which they are impractical. The consumption of cooling water by inland processing and power plants is estimated to reduce power availability for the majority of power plants by 2040–2069. While water usage is not an issue with marine engines, it forms a significant limitation for many land-based systems. In areas with land, the systems took the form of cooling ponds, in areas with limited land, such as in cities. These early towers were positioned either on the rooftops of buildings or as free-standing structures, a hyperboloid cooling tower was patented by the Dutch engineers Frederik van Iterson and Gerard Kuypers in 1918. The first hyperboloid cooling towers were built in 1918 near Heerlen, the first ones in the United Kingdom were built in 1924 at Lister Drive power station in Liverpool, England, to cool water used at a coal-fired electrical power station. An HVAC cooling tower is used to dispose of unwanted heat from a chiller, water-cooled chillers are normally more energy efficient than air-cooled chillers due to heat rejection to tower water at or near wet-bulb temperatures. Air-cooled chillers must reject heat at the higher temperature. In areas with a hot climate, large buildings, hospitals. Generally, industrial cooling towers are much larger than HVAC towers, HVAC use of a cooling tower pairs the cooling tower with a water-cooled chiller or water-cooled condenser. A ton of air-conditioning is defined as the removal of 12,000 BTU/hour, the equivalent ton on the cooling tower side actually rejects about 15,000 BTU/hour due to the additional waste heat-equivalent of the energy needed to drive the chillers compressor. This equivalent ton is defined as the rejection in cooling 3 US gallons/minute of water 10 °F. This COP is equivalent to an energy efficiency ratio of 14, Cooling towers are also used in HVAC systems that have multiple water source heat pumps that share a common piping water loop

11.
Air conditioning
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Air conditioning is the process of removing heat from a confined space, thus cooling the air, and removing humidity. Air conditioning can be used in domestic and commercial environments. Air conditioners often use a fan to distribute the air to an occupied space such as a building or a car to improve thermal comfort. The cooling is achieved through a refrigeration cycle, but sometimes evaporation or free cooling is used. Air conditioning systems can also be based on desiccants and subterraneous pipes that can distribute the heated refrigerant to the ground for cooling. In the most general sense, air conditioning can refer to any form of technology that modifies the condition of air, in common usage, though, air conditioning refers to systems which cool air. In construction, a system of heating, ventilation, and air conditioning is referred to as heating, ventilation. Since prehistoric times, snow and ice were used for cooling, the business of harvesting ice during winter and storing for use in summer became popular towards the late 17th century. This practice was replaced by mechanical ice-making machines, the basic concept behind air conditioning is said to have been applied in ancient Egypt, where reeds were hung in windows and were moistened with trickling water. The evaporation of water cooled the air blowing through the window and this process also made the air more humid, which can be beneficial in a dry desert climate. In Ancient Rome, water from aqueducts was circulated through the walls of houses to cool them. Other techniques in medieval Persia involved the use of cisterns and wind towers to cool buildings during the hot season. The 2nd-century Chinese inventor Ding Huan of the Han Dynasty invented a fan for air conditioning, with seven wheels 3 m in diameter. During the subsequent Song Dynasty, written sources mentioned the air conditioning rotary fan as even more widely used, in the 17th century, Cornelis Drebbel demonstrated Turning Summer into Winter for James I of England by adding salt to water. The introduction of air conditioning in the 1920s helped enable the great migration to the Sun Belt in the United States. In 1758, Benjamin Franklin and John Hadley, a professor at Cambridge University. Franklin and Hadley confirmed that evaporation of volatile liquids could be used to drive down the temperature of an object past the freezing point of water. They conducted their experiment with the bulb of a mercury thermometer as their object and they lowered the temperature of the thermometer bulb down to −14 °C while the ambient temperature was 18 °C

12.
Vaccine
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A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is made from weakened or killed forms of the microbe. Vaccines can be prophylactic, or therapeutic, the administration of vaccines is called vaccination. The effectiveness of vaccination has been studied and verified, for example, the influenza vaccine, the HPV vaccine. The World Health Organization reports that licensed vaccines are available to prevent or contribute to the prevention. The terms vaccine and vaccination are derived from Variolae vaccinae, the term devised by Edward Jenner to denote cowpox. He used it in 1798 in the title of his Inquiry into the. Variolae vaccinae. known. the Cow Pox. In 1881, to honor Jenner, Louis Pasteur proposed that the terms should be extended to cover the new protective inoculations then being developed, vaccines have historically been the most effective means to fight and eradicate infectious diseases. Limitations to their effectiveness, nevertheless, exist, sometimes, protection fails because the hosts immune system simply does not respond adequately or at all. Lack of response commonly results from factors such as diabetes, steroid use. Adjuvants commonly are used to boost immune response, particularly for older people, the efficacy or performance of the vaccine is dependent on a number of factors, the disease itself the strain of vaccine whether the vaccination schedule has been properly observed. Idiosyncratic response to vaccination, some individuals are non-responders to certain vaccines, assorted factors such as ethnicity, age, or genetic predisposition. If a vaccinated individual does develop the disease vaccinated against, the disease is likely to be less virulent than in unvaccinated victims, in 1958, there were 763,094 cases of measles in the United States,552 deaths resulted. After the introduction of new vaccines, the number of cases dropped to fewer than 150 per year, in early 2008, there were 64 suspected cases of measles. Vaccines have contributed to the eradication of smallpox, one of the most contagious, other diseases such as rubella, polio, measles, mumps, chickenpox, and typhoid are nowhere near as common as they were a hundred years ago. As long as the vast majority of people are vaccinated, it is more difficult for an outbreak of disease to occur. This effect is called herd immunity, polio, which is transmitted only between humans, is targeted by an extensive eradication campaign that has seen endemic polio restricted to only parts of three countries. However, the difficulty of reaching all children as well as cultural misunderstandings have caused the anticipated eradication date to be missed several times, vaccination given during childhood is generally safe

13.
Quinolone antibiotic
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The 2- and 4-quinolones are a class of bicyclic molecules, organic chemical structures that are related to the heteroaromatic coal tar isolate quinoline, see image at right. Specific quinoline molecules substituted with a functional group at carbons 2 and 4 are most often observed in isomeric forms termed 2- and 4-quinolones. Hence, they are useful in antibacterial therapy. An example of such a 4-quinolone is cipro, where the atoms of quinoline can be traced within this related structure, ciprofloxacin is a second-generation fluoroquinolone antibacterial, introduced by Bayer AG and still in wide use as the second decade of the new millennium begins. An example of such a synthesis is the Camps cyclization, which, depending on exact starting materials and reaction conditions, such hydroxy-substituted quinolines are, most often, not distinguished from a particular isomeric form termed a tautomer. These tautomerizations are represented in the images at right by the process in closely related structures. 4-Quinolones are a family of synthetic broad-spectrum agents used as anti-bacterial agents, nalidixic acid was discovered by George Lesher and coworkers in a chemical distillate during an attempt at synthesis of the chloroquinoline antimalarial agent, chloroquine. Naphthyridone and quinolone classes of antibiotics prevent bacterial DNA replication by inhibition of DNA unwinding events and this first, nalidixic acid generation included other such quinolone drugs as oxolinic acid, pipemidic acid, and cinoxacin, all introduced in the 1970s. Each proved to be only marginal improvements over nalidixic acid, researchers divide the quinolones into generations based on their antibacterial spectrum. The earlier-generation agents are, in general, more narrow-spectrum than the later ones, the only universal standard applied is the grouping of the non-fluorinated drugs found within this class within the first-generation heading. As such, there exists a variation within the literature dependent upon the methods employed by the authors. Some researchers group these drugs by patent dates Some by a specific decade Others by the structural changes The first generation is rarely used today. The drugs most frequently prescribed today consist of Avelox, Cipro, Levaquin, cinoxacin flumequine nalidixic acid oxolinic acid piromidic acid pipemidic acid rosoxacin Second-generation. The second-generation class is subdivided into Class 1 and Class 2. Ciprofloxacin enoxacin fleroxacin lomefloxacin nadifloxacin norfloxacin ofloxacin pefloxacin rufloxacin Third-generation, unlike the first- and second-generations, the third-generation is active against streptococci. Balofloxacin grepafloxacin levofloxacin pazufloxacin sparfloxacin, temafloxacin tosufloxacin Fourth-generation, fourth generation fluoroquinolones act at DNA gyrase and topoisomerase IV. This dual action slows development of resistance, clinafloxacin gatifloxacin gemifloxacin moxifloxacin sitafloxacin trovafloxacin prulifloxacin In development. Delafloxacin ozenoxacin The basic pharmacophore, or active structure, of the class is based upon the quinoline ring system

14.
1976 Philadelphia Legionnaires' disease outbreak
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The 1976 Legionnaires Disease outbreak also known as Legion Fever, refers to the first known cases of infection by Legionella pneumophila in the United States. On July 21,1976, the American Legion opened its annual convention at the Bellevue-Stratford Hotel in Philadelphia, Pennsylvania. More than 2,000 Legionaires, mostly men, attended the convention, the date and city were chosen to coincide with America’s celebration of the 200th anniversary of the signing of the US Declaration of Independence at Philadelphia in 1776. On July 27, three days after the convention ended, Legionnaire Ray Brennan, a 61-year-old retired US Air Force captain, Brennan had returned home from the convention on the evening of July 24 complaining of feeling tired. On July 30, another Legionnaire, Frank Aveni, aged 60, also died of an apparent heart attack, all of them had been convention attendees. Twenty-four hours later, on August 1, six more Legionnaires died and they ranged in age from 39 to 82, and, like Ray Brennan, Frank Aveni, and the three other Legionnaires, all had complained of tiredness, chest pains, lung congestion, and fever. Three of the Legionnaires had been patients of Ernest Campbell, a physician in Bloomsburg, Pennsylvania and he contacted the Pennsylvania Department of Health. Officials at the American Legion also began getting notices of the deaths of several members. Within a week, more than 130 people, mostly men, had been hospitalized and this finding prompted new regulations worldwide for climate control systems. Complicating the situation was a fear among the public that the cluster of 14 cases, six of whom died all within days of each other. The total number of cases reached 211, and of those,29 had died, at the time of the outbreak, epidemiological investigation protocols did not include active participation by both the laboratory specialists and investigators. No effective communication existed between scientists in the field interviewing patients, and those in the laboratory testing specimens and it had not been considered previously because it was believed to affect only animals. The bacterium was later named Legionella pneumophila,1999 Bovenkarspel legionellosis outbreak Legionella pneumophila Legionellosis Legionnaires disease List of Legionellosis outbreaks 1976 Philadelphia Legionnaires disease outbreak at DMOZ

15.
Incubation period
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Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent. In a typical infectious disease, incubation period signifies the period taken by the organism to reach a threshold necessary to produce symptoms in the host. Which is shorter depends on the disease, a person may be a carrier of a disease, such as Streptococcus in the throat, without exhibiting any symptoms. Depending on the disease, the person may or may not be contagious during the incubation period, during clinical latency, an infection is subclinical. With respect to viral infections, in clinical latency the virus is actively replicating and this is in contrast to viral latency, a form of dormancy in which the virus does not replicate. An example of latency is HIV infection. HIV may at first have no symptoms and show no signs of AIDS, despite HIV replicating in the lymphatic system, the terms intrinsic incubation period and extrinsic incubation period are used in vector-borne diseases. The intrinsic incubation period is the time taken by an organism to complete its development in the definitive host, the extrinsic incubation period is the time taken by an organism to complete its development in the intermediate host. For example, once ingested by a mosquito, malaria parasites must undergo development within the mosquito before they are infectious to humans, the time required for development in the mosquito ranges from 10 to 28 days, depending on the parasite species and the temperature. This is the incubation period of that parasite. If a female mosquito does not survive longer than the incubation period. After a mosquito successfully transfers the parasite to a human body via a bite, the time between the injection of the parasite into the human and the development of the first symptoms of malaria is its intrinsic incubation period. When possible, it is best to express the mean and the 10th and 90th percentiles, the values below are arranged roughly in ascending order, although in some cases the mean had to be inferred. For many conditions, incubation periods are longer in adults than they are in children or infants, gestation period Prodrome Quarantine Window period, the time between infection and when lab tests can identify the infection. The window period may be longer or shorter than the incubation period

16.
Radiology
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Radiology is a specialty that uses medical imaging to diagnose and treat diseases seen within the body. Interventional radiology is the performance of medical procedures with the guidance of imaging technologies, the acquisition of medical images is usually carried out by the Radiographer, often known as a Radiologic Technologist. Depending on location, the Diagnostic Radiologist, or Reporting Radiographer, then interprets or reads the images and produces a report of their findings and this report is then transmitted to the Clinician who requested the imaging, either routinely or emergently. Radiographs are produced by transmitting X-rays through a patient, the X-rays are projected through the body onto a detector, an image is formed based on which rays pass through versus those that are absorbed or scattered in the patient. Röntgen discovered X-rays on November 8,1895 and received the first Nobel Prize in Physics for their discovery in 1901, in film-screen radiography, an X-ray tube generates a beam of X-rays, which is aimed at the patient. The film is then developed chemically and an image appears on the film, film-screen radiography is being replaced by computed radiography but more recently by digital radiography and the EOS imaging. In the two latest systems, the X-rays strike sensors that converts the signals generated into digital information, in digital radiography the sensors shape a plate, but in the EOS system, which is a slot-scanning system, a linear sensor vertically scans the patient. Plain radiography was the imaging modality available during the first 50 years of radiology. Due to its availability, speed, and lower costs compared to other modalities, also despite the large amount of data in CT scans, MR scans and other digital-based imaging, there are many disease entities in which the classic diagnosis is obtained by plain radiographs. Examples include various types of arthritis and pneumonia, bone tumors, fractures, congenital skeletal anomalies, mammography and DXA are two applications of low energy projectional radiography, used for the evaluation for breast cancer and osteoporosis, respectively. Fluoroscopy and angiography are special applications of X-ray imaging, in which a fluorescent screen and this allows real-time imaging of structures in motion or augmented with a radiocontrast agent. Two radiocontrast agents are presently in common use, barium sulfate is given orally or rectally for evaluation of the GI tract. Iodine, in multiple forms, is given by oral, rectal, intra-arterial or intravenous routes. Iodine contrast may also be concentrated in areas more or less than in normal tissues. CT imaging uses X-rays in conjunction with computing algorithms to image the body, in CT, an X-ray tube opposite an X-ray detector in a ring-shaped apparatus rotate around a patient, producing a computer-generated cross-sectional image. CT is acquired in the plane, with coronal and sagittal images produced by computer reconstruction. Radiocontrast agents are used with CT for enhanced delineation of anatomy. Although radiographs provide higher resolution, CT can detect more subtle variations in attenuation of X-rays

17.
Legionella pneumophila
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Legionella pneumophila is a thin, aerobic, pleomorphic, flagellated, nonspore-forming, Gram-negative bacterium of the genus Legionella. L. pneumophila is the human pathogenic bacterium in this group and is the causative agent of Legionnaires disease. L. pneumophila is a Gram-negative, nonencapsulated, aerobic bacillus with a single and it is aerobic and unable to hydrolyse gelatin or produce urease. L. pneumophila is neither pigmented nor does it autofluoresce and it is oxidase- and catalase-positive, and produces beta-lactamase. L. pneumophila colony morphology is gray-white with a textured, cut-glass appearance, it also requires cysteine and it grows on yeast extract in opal-like colonies. While L. pneumophila is categorized as a Gram-negative organism, it stains poorly due to its unique lipopolysaccharide content in the leaflet of the outer cell membrane. The bases for the antigen specificity of this organism are located on the side chains of its cell wall. At least 35 different serovars of L. pneumophila have been described, sera have been used both for slide agglutination studies and for direct detection of bacteria in tissues using fluorescent-labelled antibody. Specific antibody in patients can be determined by the fluorescent antibody test. ELISA and microagglutination tests have also successfully applied. Legionella stains poorly with Gram stain, stains positive with silver, in the USA, about 30 infections with L. pneumophila appear per 100,000 residents per year. The infections peak in the summer, within endemic regions, about 4% to 5% of pneumonia cases are caused by L. pneumophila. In humans, L. pneumophila invades and replicates inside macrophages, the internalization of the bacteria can be enhanced by the presence of antibody and complement, but is not absolutely required. Internalization of the bacteria appears to occur through phagocytosis, however, L. pneumophila is also capable of infecting nonphagocytic cells through an unknown mechanism. A rare form of known as coiling phagocytosis has been described for L. pneumophila. Once internalized, the bacteria surround themselves in a vacuole that does not fuse with lysosomes that would otherwise degrade the bacteria. In this protected compartment, the bacteria multiply, the bacteria use a type IVB secretion system known as Dot/Icm to inject effector proteins into the host. These effectors are involved in increasing the ability to survive inside the host cell

The first practical TEM, originally installed at IG Farben-Werke and now on display at the Deutsches Museum in Munich, Germany

The electron source of the TEM is at the top, where the lensing system (4,7 and 8) focuses the beam on the specimen and then projects it onto the viewing screen (10). The beam control is on the right (13 and 14)

A 1902 engraving of "Barnard's fanless self-cooling tower", an early large evaporative cooling tower that relied on natural draft and open sides rather than a fan; water to be cooled was sprayed from the top onto the radial pattern of vertical wire-mesh mats.

Five stages of biofilm development: (1) Initial attachment, (2) Irreversible attachment, (3) Maturation I, (4) Maturation II, and (5) Dispersion. Each stage of development in the diagram is paired with a photomicrograph of a developing P. aeruginosa biofilm. All photomicrographs are shown to the same scale.

Mats of bacterial biofilm color the hot springs in Yellowstone National Park. The longest raised mat area is about half a meter long.

Two black light fluorescent tubes, showing use. The longer tube is a F15T8/BLB 18 inch, 15 watt tube, shown in the bottom image in a standard plug-in fluorescent fixture. The shorter is an F8T5/BLB 12 inch, 8 watt tube, used in a portable battery-powered black light sold as a pet urine detector.

The primitive nature of medieval medicine rendered Europe helpless to the onslaught of the Black Death in the 14th century. Fragment of a miniature from "The Chronicles of Gilles Li Muisis" (1272-1352). Bibliothèque royale de Belgique, MS 13076-77, f. 24v.

A lysosome is a membrane-bound organelle found in nearly all animal cells. They are spherical vesicles which contain …

TEM views of various vesicular compartments. Lysosomes are denoted by "Ly". They are dyed dark due to their acidity; in the center of the top image, a Golgi Apparatus can be seen, distal from the cell membrane relative to the lysosomes.

The lysosome is shown in purple, as an endpoint in Endocytotic sorting. AP2 is necessary for vesicle formation, whereas the Mannose-6-receptor is necessary for sorting Hydrolase into the Lysosome's lumen.